Clutch-facing.



S. SIMPSON CLUTCH FACING. APPLICATION rm FEB. 11'. 19:1. RENEWED sEL'u. 191s,

' Patented 0015.8, 191&

I '15 by clutch facings in general.

SUMNER smrson', or Bnmenrom, connncrron'r, ASSIGNOR TO THE BAYBESTOS COMPANY, OF BRIDGEPORT, oonnnc'rrcn'r. A CORPORATION or CONNECTICUT.

CLUTCH-FACING.

Specification of Letters Patent.

Patented Oct. 8, 1918.

Application filed February 17, 1917,'Seria1 No. 149,267. Renewed September 11, 1918. Serial No. 2 53,648.

1% reference to the various types of automobile clutches.

It is well known that there are two highl important qualities which, on account the nature of the work they are called upon to perform, should be possessed First, they should obviously have a high coefiicient of friction, and, second, having a high coefficient of friction and being constantly subjected when in use to powerful abrasive forces, and being necessarily yielding, they should be exceedingly tough in order to withstand for a reasonably long time the excessive wearing strains of use, Particularly in the case of an automoblle clutch,

the replacing of the clutch rings in a laborious and expensive operation, and every effort has been made to produce these rings from material having a requisltely high coefficient of friction and which will withstand the strains of use Ior the longest possible period of time.

It will be apparent, however, that in additionand incident to the two essential qualities mentioned above, in view of the 85 heat which is produced by the friction, clutch rings or facings should be constructed of material capable of being brought to high temperatures without either physical or chemical change thereof, and on to this account asbestos has been generally emloyed as the base for clutch-ring material,

or asbestos is not only well known to be a substance which is capable of withstanding high temperatures without chemical or physical change, but it also possesses the requisitely high coefiicient of frlctlon and vcomparatlvel good wearing qualitles.

In the mimn of asbestos, the mine run includes relative y long fibers, known as crude to asbestos, the only part of the run that can at I, SUMNER SIMPSON, a

be used for spinning," and relatively short fibers, known as fiber-asbestos, which cannot be spun. In approved present known processes, the crude asbestos is shipped to the spinnin mi'll, where it is crushed, opened, car ed, roved and spun, and then twlsted around a metallic core, usually small-gage brass or copper wire, in-as many plies as may be required by the particular one of the various purposes for which this 80 yarn is adapted. This yarn is then woven 1nto what may be termed a tape of the desired width and thickness, and of any convenient length, from which is cut rings of the desired inside and outside diameter 6E5 which are then chemically treated and baked. at a proper temperature to make the same coherent,- tough, relativelyhard and caused to possess the desired coefficient of friction.

With respect to this old process, it will be noted, first, that only a certain selective part of the mined asbestos can be employed'that is to say, the crude or longfiber asbestos-and second, that the spinning of these long fibers, into a filament, the twisting of this filament around the metallic core to form reinforced metallic yarn, the weaving of this yarn into fabric, the cutting of this reinforced fabric into rings of-the proper dimensions, and the so treating and baking of these rings, constitutes a somewhat elaborate, complex and necessarily expensive process, the product of which at best is far from perfect. That the product is defective is due to two principa causes; first, because in forming, treating and pressing rings of woven fabric it is absolutely impossible, under' any known method, to produce a ring which will hold correct inside and outside diameters and'w uniform thicknesseven assuming that a ring of woven material can be originally formed and compressed to an exact size, which experience has demonstrated to be a practical impossibilityand,- second, 'because woven fabric, however treated, is always subject to a tendency to ravel, particularly after having been worn to a cortain extent.

The present invention has in view the production of asbestos-base clutch rings, in which carding,- roving, spinning, twisting and weaving of the raw material. is entirely dispensed with, in which the short-fiber asbestos of the mine run may be utilized, which shall be not only of originally substantially uniform predetermined dimen sions and contour, but of a character to preserve the original size, contour, and other qualities and characteristics throughout long-continued use thereof.

In the accompanying drawing forming a part of this specification,

Figurel is a perspective view ofa clutch facing, embodying the present invention, partly broken away;

Fig. 2 a section on anenlarged scale on the line 22, in Fig.1, lodking in the direction of the arrows; and

V Fig. 3 is a sectional perspective view illustratin a variant form of the invention.

10. enotes the body of my novel clutch facin which is a solid homogeneous mass of as estos fiber cohering through a suitable binder, 11 wire rings embedded in the mass, and in Fig. 3, 12 denotes short lengths of mm indiscriminately dispersed throughout the mass.

In theproduction of m novel .clutch facings I take the short-fi er asbestos stock from the mines, mix the same by an approved process of saturation with a sultable liquid hinder or binding compound, mold the same under compression to the desired form and size and thoroughly dry the same either in the air or by passing it through a suitable oven. In this manner,,not only am I enabled to'utilize what is known as'lowgrade asbestos fiber, but to produce clutch rings which experiments have demonstrated will wear longer, give much better results and be more efiicient in every way than the woven endless or joined rings or facings. Furthermore, by molding under compression afring or facing from a homogeneous mass 0 riedon without the excessive waste of mate- 'rial, which cannot be avoided under present methods of cutting these rings from woven fabric. Still furthermore, it will be apparent that in mixing the materials to produce the plastic mass from which the rings are molded, Iam enabled to insure saturation of the asbestos fiber with the binding material to a much more nearly perfect degree than is possible in the attempted saturation of formed ringscut from woven fabric.

I may still further improve the product by incorporating in the plastic compound prior to compression metal wire, preferably copper or brass wire which may be in the form of rings, or a woven mesh or short lengths of wire may be indiscriminately dis- This, metallic gamated through any preferred manner of homogeneityplastic material, the manufacture is carreinforcement imparts to the finished rings 1 additional strength, rigidity and toughness.- t It is required that the fibers and the binder be thoroughly commingled or amalagitation in a suitable container for such period of time as maybe r uired to insure complete saturation of. the %bers, and that after molding the rin s be thoroughly dried, ordinarily in a heater? oven.'

The proportions of theingredients to be employed is a matter of individual judgment. The ultimate object is to produce a solid homogeneous body in which the fiber predominates. Therefore, just enough of the binding liquid should be employed to saturate the fiber to an extent which insures substantial solidity and homogeneity under compression.

Uniform density is a matter of prime consideration in. the production of these rings, for if the density-varies the effects of wearing will be unevenly distributed and thus tend to shorten the useful life of the product. By saturating and thoroughly intermingling the fibers prior to compression ofthe same to the desired annular form, much more nearly perfect uniform density of the mass of the finished roduct is insured.

I might also mention that in all asbestos yarn as now manufactured, the use of a certain amount of cotton is necessary in order that the asbestos fibers may be picked up and carried over the card. The existence of even a comparatively small amount of cotton in clutch-ring material is manifestly objectionable, but its presence therein has been necessitated in the manufacture of rings from woven asbestos. It will be noted that in carrying out my present invention the use of cotton or an equivalent thereof is wholly unnecessary.

The hinder or binding compound to which I have referred may consist of various vegetable oils or gums, or mineral oils or gums, 11s or any derivative of either or combination of both. Asphaltic compounds may also be employed, or any one of various organic or inorganic solutions of primarily viscous and subsequently hardening character, in brief 115 any substance that will not only efiect the desired cohesion between the fibers but also be water-proof and oil-proof, and possess the essential heat and wear'resisting qualities.

It may be that there are fibrous materials other than asbestos which might form the base of amaterial adapted to be used as a clutch ring or facing, such 'substitutive A fibrous material being either vegetable or mineral. In the foregoing specification I have specified asbestos fibers as a preferred base for the material of my improved clutch ring on accountof its proven and recognized heat and wear-resisting qualities and its comparatively high coeflicient of friction. 180 i I claim as new anddesire to secure by homogeneous, annular body formed of as- Letters Patent: bestos fibers cohering through a suitable 1. A clutch facing comprising a solid, binder, and having a reinforcement of me- 10 homogeneous, annular body formed of as- .tallic wire embedded inthe material thereof.

5 best/0's fibers cohering through a suitable In testimony whereof I aflix'my signature.

binder. v I

2. A clutch facing comprising a solid, SUMNER SIMPSON. 

